Free radical formation plays a destructive role in biological processes of living things, Pryor, W.A., Free Radicals in Biological Systems, Scientific American, Vol. 223, No. 2, pp. 70-83, August 1970, Pryor, W. A., Free Radical Pathology, Chemical and Engineering News, June 7, 1971, p. 34ff, and Harman, D., The Aging Process, Proc. Natl. Acad. Sci., U.S.A., Vol. 78, No. 11, pp 7124-7128, Nov. 1981. It has been found that exposure of human skin to ultraviolet radiation and air pollutants could result in the generation of free radicals in the exposed skin which could lead to premature aging of such skin. Accordingly, a topical skin treatment composition which could inhibit generation or deactivation of free radicals in the skin resulting from exposure to ultraviolet radiation and/or air pollutants would indeed be most a welcome addition to the skin treatment field.
Vitamin E (.alpha.-tocopherol) which has the structure ##STR1## has been employed to inhibit oxidation of oils and fats in foods, cosmetic preparations and drugs and for its soothing and antiinflammatory properties. It has also been found that a number of 6-hydroxychromans, including rac-6-hydroxy2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox C) which has the structure ##STR2## exhibit antioxidant activity (Scott et al, "Antioxidant Properties of 6-Hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid, Cosmetics and Toiletries, Vol. 91, Nov. 1976).